This disclosure relates generally to air data systems, and more particularly to air data systems that combine inertial sensor measurements and pneumatic pressure measurements for generating aircraft air data parameters.
Modern aircraft often incorporate air data systems that calculate air data outputs based on measured parameters collected from various sensors positioned about the aircraft. For instance, many air data systems utilize air data probes that measure pneumatic pressure of airflow about the aircraft exterior to generate aircraft air data outputs, such as angle of attack, calibrated airspeed, Mach number, altitude, altitude rate (i.e., aircraft vertical speed), or other air data parameters. Such air data parameters are then output to consuming systems, such as aircraft flight management systems, flight control systems, stall protection systems, and other consuming systems that utilize the air data parameters for operational control of the aircraft.
Often, air data systems generate an altitude rate output by differentiating the altitude parameter derived from the measured pressures. Because such numerical differentiation techniques typically amplify the high frequency components of the pressure-based measurements, the resulting altitude rate is often processed through low-pass filters that pass signals with frequencies lower than a cutoff frequency and attenuate signals with frequencies higher than the cutoff frequency. Such low-pass filtering techniques, however, typically rely on past data and introduce lag, thereby decreasing the dynamic response of the altitude rate output.